Any more of this and America's sprinters will be able to sing the words of The Star-Spangled Banner to the tune of the Jamaican national anthem. With the four Olympic sprint finals concluded last night in Beijing's National Stadium the score was: United States (population 300m; sprinting legacy, unmatched) 0, Jamaica (population 2.7m; sprinting legacy, excellent but hardly dominant in the greater scheme of things) 4.

Some described that scoreline as embarrassing for a nation that has long led the world on the Olympic track, but when the American sprint relay teams, both men's and women's, dropped the baton in last night's heats redemption's final chance disappeared and the only word left was humiliation. "I don't know what happened," said Torri Edwards, who arrived in Beijing as the favourite for the women's 100m and departed with nothing.

Edwards was referring to her botched exchange with team-mate Lauren Williams, but she was scarcely more illuminating a few minutes later when asked to explain why the US sprinters had been routed by their Jamaican counterparts: "I guess it's just not our track meet." Her male team-mates were equally bemused. "I'm a veteran. I have never dropped a stick in my life," said Tyson Gay who, like Edwards, will leave China with only the suitcase he arrived with.

There was success for the Americans in the men's 400m, where LeShawn Merritt led a clean sweep of the medals for the US, but even that triumph came with a puzzle; whatever happened to Jeremy Wariner, who many predicted would break Michael Johnson's longstanding world record of 43.18sec this week and possibly go under 43sec? Wariner looked a shadow of his own reputation as he capitulated coming down the straight last night and only just clung on to the silver medal position.

Another American silver medal winner was Allyson Felix, but, like Wariner, she too arrived in China with a big reputation and the expectation of winning gold. In the end she was beaten, as she was at Athens in 2004, by the Jamaican Veronica Campbell-Brown, with another Jamaican, Kerron Stewart, taking the bronze.

Campbell-Brown pointed out that Jamaica had a tradition of producing top sprinters such as Merlene Ottey and Don Quarrie, adding: "It doesn't matter how big or small your population is. If people are motivated and are trying hard to compete, you are going to have success."

Beyond such public utterances, the atmosphere, at least from an American perspective, might be described as sceptical. At these Games suspicion has never been far away from a sprinter whose performances catch the eye and that has certainly been the case with the Jamaican sprinters. In the absence of evidence any whisperings about the island's success can be dismissed as sour grapes. Indeed, the view of the Jamaican camp is that tougher drug testing is one of the keys to their success, especially when it comes to beating the Americans.

"This time the playing field is even, and we want it even more so," said Debbie Ferguson-McKenzie, who finished seventh in the women's 200m. "In the past, some of them have taken drugs, some have not. Marion Jones, she dominated for so long, she stood in public and said she didn't do them."

Warren Blake, a Jamaican team doctor and one of the heads of their anti-doping programme, was blunter.

He said "The playing field is more level these days. The push by the World Anti-Doping Agency and other anti-doping agencies to eradicate drugs - we feel that has helped Jamaica."